1. Field
The present disclosure relates to a yeast cell with inactivated or depressed pyruvate carboxylase and a method of producing lactate using the yeast cell.
2. Description of the Related Art
Lactate is an organic acid that is broadly used in various industrial fields, such as food, pharmaceutics, chemicals, and electronics. Lactate is colorless, odorless, and a low-volatile material that dissolves well in water. Lactate is non-toxic to the human body and thus may be used as a flavor agent, a taste agent, or a preserving agent. Also, lactate is an environment-friendly alternative polymer material and a raw material of a polylactic acid (PLA) that is biodegradable plastic.
PLA is a polyester-based resin that is produced by ring-open polymerizing a dimer, i.e., lactide, which has been converted from lactic acid and may be variously processed into a film, sheet, fiber, plastic, etc. Thus, demands for PLA as bioplastic have recently increased to broadly replace conventional typical petrochemical plastic, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polystylene (PS).
In addition, lactate includes both a hydroxyl group and a carboxyl group at the same time and thus is highly reactive. Accordingly, lactate is easily converted into an industrially important compound, such as lactate ester, acetaldehyde, or propyleneglycol, and thus has received attention as an alternative chemical material of the next generation in chemical industry.
Currently, lactate is produced by an industrially petrochemical synthesis process and a biotechnological fermentation process. The petrochemical synthesis process is performed by oxidizing ethylene derived from crude oil, preparing lactonitrile through addition of hydrogen cyanide after acetaldehyde, purifying by distillation, and hydrolyzing by using chloric acid or phosphoric acid. Also, the biotechnological fermentation process is used to manufacture lactate from a reproducible carbon hydrate, such as, starch, sucrose, maltose, glucose, fructose, or xylose, as a substrate.
Therefore, a strain for efficiently producing lactate and a lactate production method using the strain are needed.